During exercise, the recommended maximum heart rate in beats per minute is modeled by the formula m = 176 − 0.8a, where m is the maximum heart rate and a is the person’s age. solve the formula for a. at what age would you have a recommended maximum heart rate in beats per minute of 140?

1. To solve the formula  for A, the first thing we are going to do is subtract M for both sides of the equation:


Next, we are going to add 0.8A to both sides of the equation:


Finally, we are going to divide both sides of the equation by 0.8:



2. Now, to find at what age the maximum heart rate in beats per minute should be 140, we are going to replace M with 140 in our formula:




We can conclude that 45 years old person, must not exceed a heart rate of 140 beats per minute during exercise.